512 Dr. A. Alcock — A Revision 



exopodite being longer than the endopodite. In the first 

 pair there are no endopodites, but in the male their place is 

 taken by a pair of more or less rigid, longitudinally pleated, 

 or convoluted plates, known as the " petasma'^ or " audricum/' 

 Avhicli together form a tube or canal. In the second pair 

 the endopodite carries at its base in the male a fleshy 

 papilla. 



According to Zittcl, the first remains of Peneus, so far as 

 is known at present, appear in the Lithographic Slates of 

 Bavaria (Jurassic). 



The forms included in the maniple Peneus are found in 

 greatest abundance off" the coasts of the Indo-Pacific, from 

 the Red Sea and east coast of Africa (as far as 33° S.) east- 

 wards to Japan and Australia. Eastwards of this centre a 

 few species occur in the western meridians of the Pacific, up 

 to the shores of California and Panama ; and westwards of 

 it three species are found in the Mediterranean, two of 

 which extend into the N. Atlantic (one of them ranging as 

 far north as St. George's Channel), and about ten occur off 

 the Atlantic coasts of America, from New England, through 

 the Gulf of Mexico and Caribbean, doubtfully as far south 

 as the northern end of Patasouia. 



Taking the distribution of the several genera of the phratry 

 or maniple (or subgenera of the genus) in order : — 



Peneus (s. r.) has the widest range, being found all round 

 the globe, from the Gulf of Mexico, through the Atlantic 

 coasts of N. Africa, the Mediterranean, the Ked Sea, and 

 the Indo-Pacific, to California and Panama. 



Heteropeneus has been found only in the East Indian 

 Archipelago (Singapore and Japan). 



Parapeneus occurs in the West Indies and ofi" the Atlantic 

 coast of the U.S. America, in the Mediterranean and its 

 western approaches, and in Oriental seas from India to Fiji, 



Metapeneus : this large genus is almost entirely Indo- 

 Pacific (Red Sea to Polynesia), two doubtful species being 

 found in the West Indies. 



Parapeneopsis is confined to the Indo-Pacific, ranging 

 from India to China and Japan. 



Xiphopeneus is confined to the Atlantic coasts of sub- 

 tropical and tropical America. 



